For example, an inverted-F antenna is known as an antenna to be mounted on an electronic device. As an example, Patent Literature 1 discloses an inverted-F antenna that is capable of adjusting the inductance and capacitance by the length and area, respectively, of a power supply line disposed parallel to a radiation patch.
Here, when the case of an electronic device is composed of a conductor such as a metal like magnesium alloy, in order to ensure the radiation characteristic of the antenna like the above provided within the case, the case is provided with an opening in many cases. An antenna cover composed of a resin or the like is installed on the opening.